/register drew the whole form under SSO-only — name, email, password
twice, invite code, Sign Up — and only the POST refused it. That is
asking somebody for four fields and a password they will never use
before telling them the door does not exist.
/auth/signup-policy is the question the form already asks, so it answers
it: sso_only, the provider's name, and registration_open false whenever
single sign-on is the only way in. The page says one line instead. The
Register tab on the landing modal and the Register button in the header
go with it — and the modal falls back to Sign in if it was opened
straight into Register.
The sign-in page needed nothing: it already hid its "Sign up" link on
registration_open false, which is now also true under SSO.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TqXevQJhxFrM7jJg82cgZN
282b6a25f7